1. Field of the Invention
The present invention relates to: an image processing apparatus for an endoscope, the image processing apparatus to which, any of a plurality of insertion units respectively having imaging devices with numbers of pixels different from one another mounted therein, is detachably connected and which processes an image signal captured by that imaging device to output the processed image signal as image data; an endoscope system; and an image processing method for an endoscope.
2. Description of the Related Art
Conventionally, endoscope apparatuses have been widely used for various tests in the medical field and the industrial field. For example, in the industrial field, endoscope apparatuses are used to perform tests in various environments such as internal tests of jet engines of aircrafts, internal tests of industrial plants, and tests of outdoor buildings. An endoscope apparatus is configured of: a scope having an elongated shape and an imaging device such as a CCD provided at a distal end thereof; and a main apparatus that processes an image captured by the imaging device. When a user of the endoscope apparatus inserts the scope inside an object to be tested, the image captured by the imaging device at the distal end of the scope is displayed on a monitor of the main apparatus, and the image is stored in a recording medium.
In recent years, as a result of higher integration in imaging devices due to development of the semiconductor technology, imaging devices having a larger number of pixels (for example, 1.3 mega pixels) than conventionally used are now installable at the distal ends of the scopes. Therefore, an endoscope apparatus, to which plural types of scopes are detachably connected, and for which a scope among these various scopes is selectable according to a test object or a test environment, is now being practically applied.
In such an endoscope apparatus, since imaging devices are driven at frequencies appropriate for their respective numbers of pixels, a plurality of internal operating clocks are settable according to types of imaging devices of scopes connected to its main apparatus. In addition, in the main apparatus, plural circuits for image signal processing are provided according to the imaging devices. In that case, if a circuit is provided for each imaging device, the circuit scale becomes complicated and the structure of the apparatus becomes large.
Therefore, in order to avoid complication of the circuits in the main apparatus, an endoscope apparatus, which performs each signal processing after down-converting the number of pixels of an image output from the imaging device to the number of pixels that is processable by an internal processor of the main apparatus, has been proposed (for example, see Japanese Laid-open Patent Publication No. 2005-118159).